Control unit



y 1961 J. FISHER 2,984,720

CONTROL UNIT Filed June 10. 1959 INVENTOR.

United States Patent "ice A CONTROL UNIT John Fisher, Cleveland, Ohio, assignor to The Warner & S wasey Company, Cleveland, Ohio, a corporation of This invention relates to a control unitand has particular relation to a control unit for controlling the actuation of a plurality of displaccable operating elements.

According to the present invention, a control unit of improved construction is provided for controlling displacement of a plurality of displaeeable operating ele ments each controlling operation of a separate switch device. The control unit includes a control member which is movable from a neutral position through each of a plurality of preselected paths for effecting displacement of the operating elements. The unit further includes means for effecting automatic resetting of the control member to its neutral position in response to release of the control member subsequent to its movement for displaeing an operating element.

The invention further provides control means displaceable in response to predetermined movement of the control member through a selected one of the paths. The arrangement is such that the control means is displaced subsequent to movement of the control member to a predetermined position in its path of movement.

According to a preferred embodiment of the invention the operating elements are utilized to operate a plurality of switch devices. The control member is in the form of a rod which normally extends along a nuetral axis. The operating elements are spaced angularly about the neutral axis for displacement along a plurality of axes each transverse to the other and all located in a common plane which is transverse to the neutral axis.

-A plurality of pivotally mounted members are located between the control rod and the operating elements such that the ends of each pivoted member engage respectively a separate one of the operating elements and the control rod. A plurality of resilient elements bias the ends of the pivoted members into engagement with the control rod and the associated operating element. The switch devices are conveniently adjustably mounted to permit movement of the switch device and their operating elements toward and away from the associated pivotally mounted members.

The control means is preferably in the form of a magnetic core of a transformer device with the core mounted for displacement along the neutral axis. A cam follower is connected to the core having a cam follower surface which is biased into engagement with the end of the control rod which constitutes a cam. The cam follower surface is configured such that movement of the control rod relative to the neutral axis effects displacement of the magnetic core along the neutral axis .with respect to the control rod.

The switch devices-may be employed to effect any desired controlling function. As an example, the switch devices may be operated in response to movement of the control rod to control the speed and direction of movement of a mechanism of a machine tool such as a lathe.

It is therefore an object of the invention to provide a control unit of improved construction for controlling the Patented May 16, 1961 displacement of a plurality of displaceable operating elements.

It is another object of the invention to provide a control unit of improved construction for controlling the operation of a plurality of switch devices each including a displaceable operating element.

It is still another object of the invention to provide a unit as defined in the preceding object wherein the switch devices are adjustably mounted to permit movement of the switch devices and their operating elements relative to associated switch actuating members.

It is a further object of the invention to provide a control unit including a control member movable relative to a neutral position through a plurality of preselected paths for displacing operating elements which are spaced angularly about the neutral axis for displacement along transverse axes included in a common plane transverse to the neutral axis.

It is still another object of the invention to provide a unit as defined in the preceding object wherein the control member is automatically reset to its neutral position in response to the release of the control member subsequent to movement thereof for displacing an operating element.

it is a still further object of the invention to provide a unit as defined in the next preceding object wherein control means is displaced along the neutral axis in response to movement of the control member relative to the neutral axis.

It is another object of the invention to provide a control unit of the character referred to which is compact, inexpensive and reliable in operation.

Other objects of the invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which- Fig. l is a view in elevation with parts shown in section and with parts removed of a control unit constructed in accordance with the teachings of the present invention;

Fig. 2 is a view taken along the line 2-2 of Fig. l; and

Fig. 3 is a view taken along the line 33 of Fig. 1.

Referring now to the drawings, there is illustrated in Fig. 1 a control unit constructed in accordance with the teachings of the present invention. The unit there shown has many and varied applications. However, it is employed with particular advantage for controlling the speed and direction of movement of mechanisms found in machine tools such as lathes. A control unit employed in this connection is described in application Serial No. 628,349, filed December 14, 1956, by John Fisher and assigned to the assignee of the present invention.

As illustrated in Fig. l, the control unit has certain elements which are supported by a suitable frame construction having a number of frame parts. The frame includes an upper cap section 1 which is secured to an intermediate section 2 having an upper portion 3 which is of substantially square configuration. The section 2 also includes a lower portion 4 of substantially square configuration.

The portions 3 and 4 of the frame section 2 are spaced in a vertical direction as viewed in Fig. l by a plurality of spaced vertically extending webs 5. 6, 7 and 8. As best shown in Fig. 3. these webs are of substantially rectangular cross section taken in a horizontal plane and are spaced angularly about the central vertical axis of the control unit. The frame construction includes a third section 9 of substantially circular configuration which is attached to the section 2 to be positioned beneath the portion 4 as shown in Fig. l. A lowermost section 10 of the frame construction is secured to the section 9 to engage the lower surface thereof, as shown in Fig. 1.

The control unit includes an operating member 11 illustrated in the form of an elongated lever or rod having a neutral position wherein the rod extends along the central vertical axis of the control unit. The rod 11 has secured thereto. in any suitable manner.,intermediate its ends, a spherical member 12 comprising a portion of a ball and socket mount for the rod ll. The ball 12 is positioned within a substantially spherical cavity formed in part by a cavity 13 in the section land a cavity 14 in the portion 3 which communicates with the cavity 13. The section 1 includes an annular recess 15 which communicates with the spherical cavity and'which houses a ring-shaped gasket: 16. i

The rod 11 includes an upper portion 17 and a lower portion 181which may constitute portions of a single, one-piece rod, or which may comprise separate and indcpendent rods which'are attached inany suitable manner. The portion 17 of the rod is actuated in any suitable man ner, such as by a manual operation,'to elfeetmovement of the lower portion 18. as'will appear hereinafter; It is observed that the rod is rockable relative to its neutral axis by means of the ball and socket mounting intermediate the rod ends.

' In the present invention rocking movement of the rod 11 is effective to control the operation of a plurality of control devices which may assume any suitable form. In the embodiment illustrated. .the devices controlled by movement of the red are in the form of switch devices 19, 20, 21 and 22 of any suitable construction. As best shown in Fig. 2. the switch devices are'spaced angularly about the axis of the rod ll when the rod is in its neutral position. In Fig. 1 these switch devices are shown as being located between the ball and socket mount of the rod 11 and the end of the portion 18 of the rod.

in order to permit actuation of the switch devices there is provided a plurality of operating elements 23. 24, 25, and 26. associatedrespectively with the switches 19. 20, 21, and 22. These operating elements are displaceable between two operating positions. each effective to establish rangement is such that each of the operating elements is displaceable along an axis transverse to the neutral axis of the rod 11. with the axes of displacement being trans: verse to one another. as illustrated in Fig. 2, and with all of these axes positioned in a common plane transverse to the neutral axis. g

In order to mount the switch devices to the frame construction. each switch device includes a casing having a pair of openings for receiving suitable screw devices which may pass through openings of an adjacent portion of the frame construc ion. As best shown in Fig- 2. the switch devices 19. 20. 2i. and 22 have associated therewith, respectively. pairs of screws 27, 28, 29, and 30 which extend through the switch casings into openings of extensions 31. 32. 33. and 34 of the webs 5, 6. 7, and 8.

in order to permit displacement of the switch operating elements in response to movement of the control rod ll, there is provided in accordance with the present invention a plurality of actuating members in the form of pivoted members or levers 35. 36. 37. and 38. Each of these levers is pivoted at a point intermediate its ends about a vertically extending axis which is spaced from and parallel to the neutral axis of the rod 11. The levers 35. 36. 37. and 38 include respectively actuatable ends 39, 40, 41 and 42 which are shown in Fig. 2 as being adjacent the control rod 11. These levers also include actuating ends 43. 44. 45. and 46 which are adjacent. respectively, the operating elements 23. 24; 25. and 26.

As best shown in Fig. 2, the levers include curved projcctions 47. 48. 49. and 50 which extend from the actuating ends into engagement with the associated operating -vided for the purpose of effecting a stop by engaging the casing of the associated switch when the associated pthe screw. To this end the d 4 l! crating elements are in the positions shown in Fig. 2 to provide a first condition of the associated switch.

The pivoted members also carry extensions 55, 56, 57, and 58, which project from the actuating ends 43, 44. 45, and 46 in directions opposite to the direction of extension of the associated curved projections. These extensions are provided to assist in supporting a plurality of biasing means illustrated in the form of helical springs 59. 60. 61, and 62, which are effective to bias the projections 47. 48, 49 and 50 into engagement with the associated op crating elements to establish the first switch condition. These springs are supported by the webs 5, 6, 7, and 8. with ends of the springs extending into suitable openings 63', 64, 65, and 66 of the webs. The springs. in addition to biasing the actuating ends of the pivoted members, also serve to urge the actuatablc ends 39, 40, 41. and 42 of the pivoted members into engagement with the rod 11, such that the rod is normally urged to extend along its vertical neutral axis. It is observed that the springs extend along transverse axes located in a common plane transverse to the neutral axis. As shown in Fig. 2, a plurality of pads 67. 68, 69, and 70 are supported by the webs 5, 6, 7, and

8 to provide smooth surfaces against which the casings of the switch devices may be mounted.

According to the present invention the switch devices are mounted so as to be adjustable relative to the actuating ends of the levers. 35, 36, 37 and 38. To this end one of the screw openings of each switch casing is made elongated in a horizontal direction as viewed in Fig. i. As there shown, the upper opening 27' of the casing for the switch 19 is elongated as are the upper openings of the remaining switch casings. This arrangement permits adjustmcnt of the switches and their operating elements toward and away from the ends 43, 44, 45 and 46 of the levers.

As shown in Fig. 2, the members 35, 36. 37, and 38 include respectively enlarged central portions 71. 72, 73 and 74 through which extend suitable securing means such 7 as studs or screws 75, 76. 77; and-'78; "'lhescscrews'cxtend along vertical axes and serve to mount the associated member for pivotal movement about the axis of screws include central portions which are loosely received in passages of the enlarged portions 71, 72, 73 and 74. The screws 75. 76. 77, and 78 serve additionally to secure the cap section 1 to the intermediate frame section 2 and for this purpose project through aligned openings of the sections 1 and 2 in threaded engagement with the section 1, as illustrated in Fig. l.

The screws also operate to support a Hat plate 79 in a horizontal plane. as shown in Fig. l, intermediate the end of the portion l8 of the rod 11 and the ball and socket mount for the rod. The plate 79 includes a pair of transverse slots providing four slot sections 30. 81. 82 and 83, as illustrated in Fig. 2. As shown in Fig. I. each of the screws 75, 76. 77. and 78 includes an enlarged portion 84 which serves to space the pivoted members from the plate 79. The slot sections in the plate 79 operate to confine the rod 11 for movement in each of four directions which are located in a pair of transverse planes which include the slot sections. Threaded nuts are applied to ends of the screws beneath the plate 79 to effect the securing action.

As best shown in Fig. l, the control unit also includes a plunger 85 which is located to extend along the neutral axis of the rod ll for displacement along the neutral axis. The plunger 85 and the rod ll have cooperating cam and cam follower means associated therewith. la the illustrated embodiment the plunger 85 has secured thereto in any suitable manner a cam follower element 86 which is located at the upper end of the plunger as viewed in Fig. l. The surface of the cam follower element 86 is biased into engagement with the end surface of the section l8 of the rod ll by suitable biasing means.

This end surface of the section 18 constitutes a cam trolling function may be effected by the control means switch. These switches may be of the type known as 2,984,720 element which drives the follower element 86. The biasing means is shown in the form of a helical spring 88 having one end located within an annular recess 87 of the undersurface of the cam. follower element and having another end in engagement with a surface of the section 5 9 of the frame construction. The spring 88 surrounds a central extension 89 of the frame section 9 which projects placement of the associated operating element is effective to transfer the switch conditions.

When the desired switch closed condition is established, the rod 11 may be released by theoperator with the result that the rod will be returned to its neutral position under the combined action of the springs 59, 60, 61, and 62. Such return of the rod 11 to its neutral position upwardly from the surface of the section 9. For a purestablishes an open condition of the associated switch. pose appearing hereinafter, the spring 88 is designed so A similar sequence of operations as described results when that its biasing force is somewhat weaker than the biasing 10 the rod 11 is moved through the other slot sections 80, 81 forces exerted by the springs 59, 60, 61. and 62. I i and 83. The upper portion 3 of the frame section 2 is As shown in Fig. 3, the cam follower element 86 has a. observed to include a tapered passage 104 having an insurface which is of generally circular configuration, havclined sidewall 105 which functions as a stop surface ing an inner circular portion 90 which lies concentrically to limit the degree of movement of the rod 11 from its with the neutral axis of the rod 11 in a plane extending 15 neutral axis. transverse to such neutral axis. The cam follower ele- In the illustrated embodiment the control means 97 is ment 86 also includes a sloping surface portion 91 surdisplaced along the neutral axis subsequent to actuation rounding the portion 90 and tapering: outwardly and of one of the switch devices caused by movement of the downwardly therefrom, as best shown in Fig. l. The cam rod from its neutral position. For this purpose the suriollower surface is designed to be substantially sym- 0 face portion 90 of the cam follower element 86 has the metrical relative to the neutral axis as shown in Fig. l. planar configuration previously described and is propor- The plunger 85 includes a body portion 92 which extio'ned so that the cam end surface of the section 18 of tends from the cam follower 86 downwardly, as viewed in h rod ri Over the Seclioh 99 until one Of the-Switch Fig. 1, through an opening .93 formed in a bushing 94 has been closed. At this time the end surface of the which fits within a passage 95 of the central extension rod'section 18 will move ofithe surface portion 90 with 89 of the frame section 9. -.The body 92 is provided the result that the cam follower element 86 and the conwith a suitable externally threaded element 96. V A suittrol means .97 willfbe b d p l y; as Viewfid' in abie control means may be attached to the body 92 by Fig. 1,untilthe surfacejportion 91 engages the end of the means of the threaded element 96. I 4 i rod section 18. ,As' described hereinbefore, the bias action In the present invention control means 97 is a ached 3 of the spring 88 is somewhat weaker than the biasing to the plunger 85 for displacement therewith along the actions of the springs59, 60, 61, and 62, with the result neutral axis of the. rod 11 in response to movement of that when the refill. is rclcased, from its switch closing the rod alongwits..preselected paths. Any desired con-- v p tiori so that the end of the rod section 18 will move to FOr example, the control means 97 may comprise force the cam follower element 86 downwardly, as viewed a magnetic core of a suitable transformer device 97', as in Fig. 1 until the 'rod' a riv s at its nclltl'fll P l described in the aforementioned Fisher.application.- herein it e gagos. the Surface p r In order to house the transformer'97 the frame con- As best Shown in Figtho 37 and struction includes the section 10 whichhas an extended 38 include beveled side surfaces 106 adjacent the ends portion 98 with an annular flange 99 which engages the 40 39, 0, 41 a These beveled surfaces engage the rod underside of the section 9. The sections 9 and 10 are section 18 when such section is moved to a switch actuatsecured to each other and to the section 2 by means of ing position to provide stable engagement between the rod suitable screws 100, 101. 102. and 103 which pass through and pivbted members. aligned openings of the section 9, the flange 99, and the Although the invention has been described with referportion 4 of the section 2. 5 ence to certain specific embodiments thereof, numerous in operation, an operator has merely to actuate the lmodificallmls 3113 Possible, and it is desired l0 Cover all upper portion17 of the rod 11 in one of the directions demodlfichtiohs Within the p a scope of the appended tcrmined by the slot sections in the plate 79. As an exclaimsi v ample, the operator may effect movement of the upper Having thus described y invchtloh, I 913ml: portion 17 of the, rod toward the left as-viewed in Fig. l. n .cohll'ol first Control '9 means having a This movement is effective to pivot the lower portion is neutral nositionwhoroin the t d moons extends alone of the rod 11 in a right hand direction. as viewed in Fig. l a first axis. mounting moons intermediate. the s of the through the slot section 820i the plate 79. This movefirst rod means m g the first rod means rocking ment effects corrcspondingmovement of theend 41 of v ntlowards and away from thetfitst aXi first b ihe member 37 to pivot the member 37 in a clockwise 5,1 in; means biasing said first rod means toward said neudirection about the axis of the screw 77 as viewed in Posillhh, 3 p r y. 0f l i p d allglllally Fig. 2. This pivotal movementimparts movement to about h first aXiS, plurality displaccahh: Switch P- the end 45 of the member 37 toward-the left as viewed r s 919316113 pa e h y .hh hfi The first axis, in Fig. 2, against the bias exerted bythe spring 61 with 3 hitch Oi id'operating elements being displaced along a the result that the operating element 25 is free-for displacement toward the left, as viewedin Fig. 2. J'l'he sev-' ment of the first rod means relativeto thefirst axis to eral operating elements may be spring biased so as to be actuate a separate one of said switches, second rod means displaced outwardly from the switch casing in response fl d 310118 the first axis r di pl n along t to movement of the rod ll from its neutral position as first a i m and Cam follower P183115 a i t W described in the above example.. r i :5 said first and second rod means, second biasing means In the embodiment illustrated, theoperating elements i g s d cam n m o r moons into c 23. 24, 25, and 26 are in positions effective to establish ment guide means confining Said first rod means for l open conditions of the associated switch devices. When 8 movement relative t0 The first axis through 3 P of the rod 11 is moved from its neutral position, as for transverse Planes, Said Cam and Ca follower m ns h example. along the slot section 82, as previously dct; Configured 50 that the Second means is displaced scribed, by a sufiieient distance, then the associated opcralong Said first axis toward lhfi first rod means in response ating element 25 is displaced outwardly from its switch to predetermined rocking movemfillt of s r t r d casing to establish a closed condition of the associated moans t f tho fi t i n tr l means owned by said second rod means for displacement therewith, the miniature snap action switches wherein a very slight displane through which the first rod means moves to displace -position the. .rodnwillmbe iorcedioward.theeneutral po'si-.

4 second axis in response to predetermined rocking move- 7 an operating element being spaced from the plane which includes the second axis of such operating element.

' 2. A unit as defined in claim 1 wherein said operating elements are located substantially in a common plane extending transverse to said first axis intermediate said mounting means and said cam.

' 3. in a control unit. an operating element displaceable along a first axis, means including a control lever for controlling displacement of said operating element, said control lever being mounted for rocking movement through a plane spaced from and parallel to said first axis between first and second spaced operating positions wherein the control lever establishes respectively first and second positions of the operating element along the first' axis, and control means movable along a second axis extending substantially'transverse to said first axis, said control means being moved along the second axis in response to preselected rocking movement "of thecontrol'lever away from one of its operating positions;

4. A unit as defined in claim 3 wherein the lever cxtendsalong said second axis when in said first operating position, said control means being moved toward the lever in response to movement of the lever towards its second position.

5. In a control unit, an operating element displaceable between two operating positions'along a first axis, a member having spaced ends mounted for pivotal movement about a second axis intermediate said ends spaced from and extending transverse to the first axis. biasing means biasing one of said ends into engagement with said operating element to establish one of said positions, and a control rod normally extending along a third axis spaced from and extending substantially parallel to said second axis. said control rod being movable out of said third axis through a plane spaced from and extending parallel to the first axis to actuate the other of said ends for moving said one end about the second axis against the bias of said biasingmea'ns, said operating element beingdisplaced in .,respons'e..to movement. of "salt Lon'e;end.sfrom;said tms.

position to the other position.

6. A unit as defined in claim 5 in combination with control means displacc able substantially along said third axis, said control means being displaced along the third axis in response to movement of said control rod out of said third axis.

7. in a switch control unit, a switch including a switch operating element, a member having spaced ends mounted for pivotal movement about a first axis intermediate said ends, a controlrod normally extending along a sccond axis substantially parallel to said first axis, first resilient means biasing one of said ends into engagement with said switch operating element, and biasing the other of said ends into engagement with said control rod. a plunger mounted to extend along said second axis for displacement along said second axis, second resilient means biasing said plunger into engagement with a terminal surface of said rod. said rod being movable out of said second axis to actuate the other of said ends for moving said one end about the first axis against the bias of said first resilient means, said switch operating element being movable in response to movement of said one end to operate the switch, said plunger being displaced along said second axis in response to a predetermined degree of movement of said rod out of said second axis. and control means carried by said plunger.

8. A unit as defined in claim 7 wherein the control means comprises a magnetic core, said plunger being dis placed along the second axis only in response to movement of said rod to the extent effective to operate said switch.

9. In a switch control unit, a control rod mounted to normally extend along a first axis for movement out of the first axis, a plurality of members each mounted intermediate its ends for movement about a second axis substantially parallel to said first axis, said second axes being spaced angularly about the first axis, a plurality of switches, a. plurality of displaceable switch operating elements each associated with one end of a separate one of the members for controlling operation of said switches, a plurality of resilient elements each biasing a separate one of said one ends into engagement with the associated operating element to force a separate one of the other of said ends into engagement with the control rod, and means guiding said control rod for movement through each of a plurality of selected paths for actuating a separate one of said other ends, the one end of the associated member beingmoved about the second axis against the bias of the associated resilient element in response to actuation of its other end .to cause displacement of the operating element for operating the associated switch.

10. A unit as defined in claim 9 in combination with control means displaceable substantially along said first axis, said control means being displaced along the first axis in response to movement of the control rod out of the first axis through a sclected one of said paths.

11. A unit as defined in claim 9 wherein said operating elements are displaceable along third axes each extending substantially transverse to said first and second axes, said third axes extending substantially transverse to one another all in a common plane.

12. In a switch control unit, a control rod mounted to normally extend along a first axis for movement out of the first axis, a plurality of members each mounted intermediate its ends for movement about a second axis. substantially parallel to said first axis, said second axes being spaced angularly about the first axis. a plurality of switches, a plurality of displaceable switch operating elements each associated with one end of a separate one of the members for controlling operation of said switches, a

' plurality of resilient elements each biasing a separate one of said one ends into engagement with the associated operating element to force a separate one of the other of said ends into engagement with the control rod, and means guiding said control rod for movement through each of a plurality o t' seleeted paths for actuating a separate one of said other ends, the one end of the associated member being moved about the second axis against the bias of the associated resilient element in response to actuation of its other end to cause displacement of the operating element for operating the associated switch, a plunger displaceable substantially along said first axis, control means carried by said plunger, and a second resilient element biasing said plunger along the first axis into engagement with an end of said rod, said plunger and control means being displaced along said first axis in response to predetermined movement of said rod through a selected one of said paths.

13. A unit as defined in claim 12 wherein the plunger includes an end surface engaging the rod lying in a plane transverse to said first axis, and a tapered surface flaring outwardly from the end surface away from the rod. said plunger being displaced along the first axis under action of the second resilient element when the rod is moved off the end surface onto the tapered surface.

14. A unit as defined in claim 13 wherein the first resilient elements exert a greater biasing force than the force exerted by the second resilient element.

15. In a switch control unit, a switch including a switch operating element, a member having spaced ends mounted for pivotal movement about a first vertical axis intermediate said ends, a control rod normally extending along a second vertical axis, first resilient means biasing one of said ends into engagement with said switch operating element, and biasing the other ofsaid ends into engagement with said control rod. 8. plunger mounted to extend along said second axis for displacement along said second axis, second resilient means biasing an end surface of said plunger into engagement with a terminal surface of said rod, said rod being movable out of said second axis to actuate said other of said ends for moving said one end about the first axis against the bias of said first resil icnt means, said switch operating element being movable along a horizontal axis in response to movement of said one end to operate the switch, said plunger having a tapered surface flaring outwardly from the end surface away from the rod and being displaced upwardly along said second axis in response to a predetermined degree of movement of said rod out of said second axis, and control means carried by said plunger, said first resilient means exerting a greater biasing force than the force exerted by the second resilient means.

16. In a control unit, a switch including a casing and a switch operating element displaceable between two operating positions along a first axis, a member having spaced ends mounted for pivotal movement about a second axis intermediate said ends spaced from and extending transverse to the first axis, biasing means biasing one of said ends into engagement with said operating element to establish one of said positions, a control rod normally extending along a third axis spaced from and extending substantially parallel to said second axis, said control rod being movable out of said third axis to actuate said-other of said ends for moving said one end about the second axis against the bias of said biasing means, said operating element being displaced in response to movement of said one end from said one position to the other position, and a stop carried by said member at said one end engaging the switch casing when the control rod extends along said third axis.

17. In a control unit, control rod means having a neutral position wherein the rod means extends along a first axis, said rod means being mounted for rocking movement through a plane towards and away from said first axis, a pair of displaceable operating elements spaced on separate sides of said plane, and separate relatively movable means operativel'y connecting each of said operating elements to said rod means, said operating elements being selectively displaced along parallel second axes substantially perpendicular to the first axis in response to movement of a selected one of said relatively movable means by predetermined rocking movement of the rod means relative to the first axis.

18. In a control unit, control rod means mounted to normally extend along a first axis and movable through a plane towards and away from the first axis, a pair of operating elements on opposite sides of the plane and displaceable along spaced parallel second axes parallel to said plane and substantially perpendicular to said first axis, separate relatively movable connections extending between each of said operating elements and said rod means, and separate resilient means acting upon each of said connections to establish first positions of said operating elements, said'connections being selectively movable against the action of the associated resilient means in response to predetermined movement of the rod means away from the first axis for causing displacement of the associated operating element from said first position to a second position, said rod means when released in a position away from the first axis being automatically returned to the first axis under the action of the connection moved by the rod means and the associated resilient means.

19. In a control unit, a control rod mounted to normally extend along a first axis for movement out of the first axis, a plurality of members each having a pair of ends, each of said members being mounted intermediate its ends for movement about a second axis substantially parallel to said first axis, said second axes being spaced angularly about the first axis, a plurality of displaceable operating elements each associated with one end of a separate one of the members, a plurality of resilient elements each biasing a separate one of said one ends into engagement with the associated operating element to position a separate one of the other of said ends adjacent the control rod, and means guiding said control rod for movement through each of a plurality of selected paths for actuating a separate one of said other ends, the one end of the associated member being moved about the second axis against the bias of the associated resilient element in response to actuation of its other end to cause displacement of the operating element.

References Cited in the file of this patent UNITED STATES PATENTS 1,242,5 16 Britton Oct. 9, 1917 2,391,881 Clay Jan. 1, 1946 2,622,161 Harter Dec. 16, 1952 2,679,678 Stephan June 1, 1954 2,754,411 Dohrmann July 10, 1956 2,841,659 Eitel July 1, 1958 

